Radiation Biology: ARS, Dosimetry, and Somatic Effects

Mean survival time is defined as

the average survival time of those who have been exposed

Where did scientists get their evidence of biologic exposure to high doses of radiation? This is a multi-select answer

nuclear weapons testing, atomic bomb survivors, nuclear accident victims, and radiation therapy patients

During the latent stage of ARS, what symptoms does the person experience

none, they feel better

True/False: As the dose of radiation increases, the mean survival time increases

false

The prodromal stage is defined by which symptoms?

nausea, vomiting, fatigue, and leukopenia

True/False: The primary effect of radiation to a person is lifespan shortening

true

Which of the following are classified as early somatic effects: ulceration, fever, depressed sperm count, nausea, cataracts, skin erythema, atrophy

fever, depressed sperm count, nausea, skin erythema

Acute Radiation Syndrome results from which of the following conditions?

radiation exposure must be to the whole body, exposure comes from an external penetrating source, dose is delivered all at once

Which of the following are symptoms of the latent stage

none (they are no symptoms present)

Which of the following would be classified as late somatic effects of radiation: skin erythema, fibrosis, permanent sterility, cataracts, dry or moist desquamation, alopecia, fever, ulcerations

fibrosis, permanent sterility, cataracts, and ulcerations

True/False: the circulating blood is radioresistant

true

Which of the following factors would be used in the calculation of damage to tissues from radiation exposure

the size of the area that is exposed, the amount of radiation, the type of radiation, and the specific body parts exposed

An external penetrating source of radiation would be considered

low let

A dose of 0.1 Gy can do which of the following: cause a genetic mutation, cause infertility, depress menstruation, cause an increase in the cell count

cause a genetic mutation and depress menstruation

True/False: Biologic Dosimetry is referred to as an analysis of the circulating blood in which damage to tissues is used to estimate radiation dose

true

Which of the following are only associated with the GI syndrome category?: Hemorrhage. fatigue, anemia, emaciation, electrolyte imbalance, severe NVD

emaciation, electrolyte imbalance, and severe NVD

What are early deterministic somatic effects of radiation?: Temporary sterility, cataracts, organ atrophy, fatigue, blood disorders, fibrosis

temporary sterility, fatigue, and blood disorders

Which portion of the GI tract is most sensitive

small bowel

What type of radiation exposure is necessary to see a chromosomal aberration

High or Low LET

What is one factor that determines whether damage is an early or late somatic effect

time

Which dose is considered fatal

12 Gy

True/False: If an ovum cell is lost during menstruation, it will not be replaced

true

True/False: The most differentiated sperm cell is the spermatocyte

false

Grenz rays were used to treat

ringworm

A dose of 0.25 Gy would produce

a measurable hematologic depression

In which stage would the person exposed to a large dose of radiation to their entire body, actually be feeling better

latent

In a deterministic effect, increasing the dose of radiation received will either increase or decrease the amount of damage the cell receives

increase

True/False: In a probabilistic (stochastic) effect, increasing the dose would increase the severity of the effect

false

Which of the following are stochastic effects?: Erythema, Mutinogenesis, Cancer, Teratogenesis, Cataracts

multiogenesis, cancer, and teratogenesis

Which layer of the epithelial tissue is the most radiosensitive

epidermis

Which of the symptoms below are associated with the hemopoietic syndrome (multi select): Convulsions, hemorrhage, Infection, Emaciation, electrolyte imbalance, Lethargy, vasculitis

hemorrhage and infection

Chromatid aberrations have been observed during

metaphase

ARS effects are

deterministic

As the dose increases, the survival time _________

decreases

Shock is a symptom of which syndrome

cerebrovascular

True/False: a pluripotential cell can become any type of cell found within the system

true

Which of the following mature cells can last 120 days

erythrocyte

Which cell is a radiosensitive sperm cell

spermatogonia

True/False: hematologic monitoring was done in the 1920's and 30's

true

True/False: bone marrow is radiosensitive

true

True/False: circulating blood is radioresistant

true

At what dose would you see a depression of the sperm population

0.1 Gy

True/False: in order to see an ARS syndrome symptom, a person must be exposed to - minimally - 1 Gy

true

True/False: at high doses, you would see the effect of the current syndrome AND the previous effects from the lower doses

true

Explain the miso soup theory

it is thought that seaweed that mitigate the effects of iodine-131's on the thyroid

According to the miso soup article, the Hiroshima University's Medical Research Center on Atomic Bomb Radioactivity found that fermented __________ flushed radioactive isotopes from the organs and muscle tissues of rats, which reduced the levels of inflammation in those organs

soybeans

True/False: rats fed miso that had been fermented for longer periods (ie, about 180 days) survived longer than rats that consumed miso whose soybean fermentation process had been shorter

true

What were the two most effective ingredients listed in mitigating the effects of radiation

brown seaweed and miso made with soybeans fermented for 141-180 days

The total radiation dose given to a somatic or genetic cell in the period of time in which that dose was delivered determined the rate of

chromosome aberrations

Acute radiation syndrome presents in four major response stages. In what order do these stages occur?

prodromal, latent period, manifest illness, recovery or death

Which of the following systems is the most radio-sensitive vital organ system in human beings?

hematopoietic

When cells are exposed to sub lethal doses of ionizing radiation, approximately _______ of radiation induced damage may be repaired over time in about _______ is irreparable

90%; 10%

As radiation dose increases, the severity of early tissue reactions

also increases

Prolonged exposure to X-rays in the diagnostic energy range results in high radiation dose to the skin while underlying tissues receive

a substantially less dose

In 1898 after personally developing burns attributed to radiation exposure, this Boston dentist began investigating the hazards of radiation exposure and became the first advocate of radiation protection. Who is this person?

William Herbert Rollins

In the female, the ovarian stem cells

multiply to millions of cells only during fetal development, before birth, and then steadily decline in number throughout life

Which of the following types of cells developed from single precursor cell, the pluripotential stem cell? 1. Lymphocytes and granulocytes 2. Thrombocytes and erythrocytes 3. Platelets

1, 2, and 3

With regard to radiation exposure, which part of the gastrointestinal tract is most severely affected?

small bowel

Somatic effects affect whom?

The irradiated person

Genetic effects affect whom?

Future offspring

Define mutinogenesis

Mutation of a spermatogonia or oogonia; mutation of a cell pre-conception

Define teratogenesis

Fetal exposure causing congenital abnormalities such as shunted limbs, mental retardation, club foot, and microcephaly; mutation of an embryo or fetus after conception

What are the four factors to somatic and genetic damage caused by radiation?

Size, amount, type (of radiation), body part

What is one factor that determines whether damage is early or a late somatic effect? Which one is which?

Time: Early is less than a year. Late is a year or more.

What is another term for a stochastic effect

probabilistic

List three potential consequences of radiation that are considered stochastic

cancer, teratogenesis, or mutinogenesis

What is another term for a non-stochastic effect

deterministic effect

With probabilistic effect, is the dose of radiation received directly or inversely proportional to the severity of the biologic changes in an individual?

Directly. More radiation = more probability of an effect occurring

If a patient is exposed to x-radiation during a lengthy fluoroscopic procedure, what are some potential early deterministic effects?

Skin injuries such as skin erythema (burns) and alopecia

Define alopecia

Epilation; hair loss

List three early (acute) effects of radiation

Nausea/fatigue, skin erythema, blood disorders

List three late (chronic) effects of radiation

Cataracts, fibrosis, organ atrophy

What causes skin ulceration from radiation exposure?

Occurs when the skin tissue does not heal/replenish after skin erythema

How does radiation affect the thyroid gland?

Uptakes into the thyroid and can cause thyroid cancer (thyroid is super sensitive to radiation)

What is the primary effect of radiation?

Shortened lifespan

A syndrome applies when three specific conditions are met. What are they?

When irradiation occurs: (1) acutely/in a matter of minutes, (2) over the entire body or nearly so, and (3) from an external penetrating source such as X-rays, gamma, or neutrons

What are the three syndromes that we study in relation to exposure to large amounts of radiation?

Hematopoietic, GI, and CVS system

Acute Radiation Syndrome has 4 stages of response; what are they?

Prodromal, latent period, manifest illness, recovery or death

All hemo symptoms

Nausea, vomiting, decreased # of RBCs, WBC, and platelets in circulating blood, hemorrhage, infection, anemia

All GI symptoms

Severe NVD, fever, fatigue, loss of appetite, lethargy, anemia, leukopenia, electrolyte imbalance, emaciation

All CVS symptoms

Excessive nervousness, loss of vision, confusion, lack of coordination, shock, meningitis, vasculitis, coma

How long does the prodromal stage last and what are the initial symptoms?

Days to minutes; symptoms include nausea, vomiting, diarrhea, fatigue, and leukopenia

Approximately how long does the latent period last and what is happening in this period?

Weeks to hours. During this time, the irradiated person appears healthy

Define denudation

The Crypt cells of Lieberkuhn become smaller because stem cells are damaged and unable to repopulate. The result is shortened villi, which are used for absorbing nutrients

How often are crypt cells sloughed off, and where are they located?

every 24 hours; stem cells located in the intestines (small)

What ultimately causes death in the CNS syndrome?

Increase in intracranial pressure

What is the range of dose that affects the hematopoietic syndrome?

1-10 Gy

The explosion of the reactor at Chernobyl caused what to be released into the air?

Burning graphite, uranium dioxide, cesium 137, iodine 131, and plutonium 239

Why did scientists have to use "biologic dosimetry" to assess workers' doses that were affected when the reactor exploded?

To measure their blood counts (lymphocytes and granulocytes) and attempt to figure out how much radiation they received (they did not have dosimeters, and the counters they did have were maxed out due to extreme radiation levels).

At a dose of 0-1 Gy, what is the most likely affect to the population?

Depress sperm population, delay menstruation, and/or cause genetic mutation

At a dose of 4 Gy, which system will most likely be affected

hematopoietic

At a dose of 10 Gy which systems will most likely be affected and what are the symptoms?

Gastrointestinal and hemo

What stochastic effects did the people of Japan see after the bombings of Hiroshima and Nagasaki?

stochastic effects such as thyroid and breast cancer, leukemia, and genetic mutations, as well as late deterministic effects like cataracts and sterility

What is the dose limit for a member of the public per year?

Frequent: 1 mSv Infrequent: 5 mSv

What is the dose limit for a technologist for a year?

50 mSv

What is the dose limit to a fetus?

Monthly: 0.5 mSv Entire: 5 mSv

What is the dose that we use for humans to determine LD 50/60 with medical support?

8.5 Gy

Generally, at a high dose, what is the percentage of an irradiated cell population the will be repaired?

90%

In order for a cell to repair quickly, what does it need?

Repair enzymes, oxygen, and nutritional support (oxygenated cells are rich in nutrients and aid in the healing process)

What are the three organs/systems that will demonstrate immediate effects after irradiation?

Skin, male and female reproductive organs, and bone marrow